Muscular system

Question 1

Explain the location, function and description of skeletal muscle.

Answer 1

• Location= Attached to bone
• Function= Voluntary movement
• Description= Striated

Question 2

Explain the location, function and description of cardiac muscle.

Answer 2

• Location= Walls of the heart
• Function= In-voluntary control, auto-rhythmic
• Description= Striated, uninucleate cells interlock at intercalated discs

Question 3

Explain the location, function and description of smooth muscles.

Answer 3

• Location= Walls of hollow organs
• Function= Involuntary, auto rhythmic, propels substances along internal passageways.
• Description= non-striated, cells arrange in a sheet structure.

Question 4

What are the functions of muscle?

Answer 4

• Movement
• Posture
• Regulating organ volume
• Moving substances in the body
• Heat production

Question 5

What are the different characteristics of muscle?

Answer 5

• Excitability= ability to respond to a stimulus
• Contractability= ability to contract when stimulated
• Extensibility= ability to be stretched/ extended
• Elasticity= ability to return to its original form after being stretched

Question 6

When does movement occur?

Answer 6

• When a muscle contract

Question 7

Muscles are arranged in opposing pairs, what are these called?

Answer 7

• Antagonistic pairs.
• Agonist= contracts to cause an action
• Antagonist= stretches and yields to action of the agonist
• Synergist= contracts to stabilise intermediate joints
• Fixator= stabilises origin of agonist

Question 8

What are muscle made up of?

Answer 8

• Bundles of muscle fibres called fascicles. These muscles and fibres are held together by sheets of connective tissue.

Question 9

What are the sheets of connective tissue found in muscle?

Answer 9

• Epimysium
• Perimysium
• Endomysium

Question 10

What are the different contractile proteins?

Answer 10

• Actin and myosin are the contractile proteins.
• Troponin and tropomyosin are contraction inhibiting proteins.

Question 11

What is ATP?

Answer 11

• Produces energy for muscles.
• It is produced through different metabolic pathways: Creatine phosphate, anaerobic respiration and aerobic respiration.

Question 12

What does anaerobic respiration do?

Answer 12

• Provides ATP for short, moderate durations of activity (60 secs or slightly more). It does not require O2 and has two stages: Glycolysis and lactic acid formation.
• So, breakdown of glucose into pyruvic acid (through glycolysis). It produces 2 ATP molecules per breakdown of glucose molecule. Pyruvate is then converted to lactic acid in absence of O2.

Question 13

What does creatine phosphate do?

Answer 13

• Provides ATP for first few seconds of high intensity activity.
• Creatine phosphate donates a phosphate group to ADP from ATP, it is catalysed by the enzyme creatine.
• The reaction= creatine phosphate + ADP= creatine + ATP

Question 14

What does aerobic respiration do?

Answer 14

• Provides ATP for prolonged activities: several mins- hours.
• It requires O2 and has three stages: glycolysis, kreb’s cycle, oxidative phosphorylation.

Question 15

What are some physiological changes during exercise?

Answer 15

• Increase in CO2 and lactic acid
• Increase in muscle movement
• Increase return of blood flow to the heart

Question 16

What receptors detect physiological changes?

Answer 16

• Chemoreceptors detect co2
• Proprioceptors detect muscle movement
• Baroreceptors detect blood flow to the heart

Question 17

What are the outcomes of these physiological changes?

Answer 17

• Increase ventilation and cardiac output
• Vasodilation, vasoconstriction and increased sweating etc.

Question 18

What changes do skeletal muscles go through as we age?

Answer 18

• Sarcopenia= loss of muscle mass and strength.
• Reduced muscle repair and regeneration
• Neuromuscular changes and motor neuron loss
• Increased muscle stiffness